CN112228434A - Clamping collar with fixing fingers - Google Patents

Abstract

A clamping system for connecting first and second pipes (2, 4), opposite ends of the pipes having clamping surfaces projecting from the cylindrical outer surfaces of the pipes. The system includes a collar (10) including a band (12) clampable around the clamping surface, the band (12) having first and second sides (13A, 13B) defining an internal groove (14) therebetween adapted to receive the clamping surface. The collar carries at least one fixing finger (40, 40') having a free end portion projecting axially beyond the edge of the first side face (13A), the free end portion having a rib (42) configured to be fixed on the outside of the belt by means of a radially projecting element (62).

Description

Clamping collar with fixing fingers

Background technique

The present disclosure relates to a clamping system for connecting first and second pipes, the opposite ends of the pipes having clamping surfaces projecting from the cylindrical outer surface of the pipes.

Clamping systems of this type are known, for example, from European Patents EP 1 4514 498 and EP 2 598 785 .

In such a system, the collar includes a band that can be clamped around the clamping surface of the tube. The belt has sides between which internal grooves are defined and the gripping surfaces of the tubes are placed in the internal grooves for gripping. Thus, the tubes remain clamped relative to each other. As shown in the aforementioned patent, it may be useful to pre-install a clamping system on the end of at least one tube prior to clamping.

In order to allow pre-installation on both pipes, EP 2 598 785 proposes a clamping system comprising a washer fixed relative to the collar by means of fastening lugs, and comprising first and second pre-installation lugs, said first and second pre-installation lugs Two pre-installation lugs are respectively capable of cooperating with the first and second tubes to secure the gasket, and thus the entire clamping system, with respect to the respective clamping surfaces of the tube prior to clamping. In this case, these pre-installation lugs comprise short lugs that extend rearwardly over the frusto-conical annular shape of the gasket to mate with the gripping surfaces of the tubes on which to rest between the belt and the gasket. These pre-installed lugs also include long lugs extending from the top of the gasket in the opposite direction to the gasket to mate with the clamping surfaces of the other tubes.

In EP 2 598 785 both types of lugs are elastically deformable. This arrangement is generally satisfactory, however, for some applications it is important to improve the reliability of the securing of the lugs relative to the clamping surface, especially for long lugs. In practice, for particularly long lugs, it may be difficult to ensure the correct range of elastic deformation for certain clamping diameters, especially large diameters over the range of 5 cm or more. On the one hand, it is necessary to ensure that the elastic modulus of these lugs is high enough that they have the desired elasticity to elastically return to a position after the tube is deformed when it is engaged in the clamping system to ensure the pre-conditioning of the tube. Install retention. They must then have the necessary elastic response so that they do not deform too easily when traction is applied in the direction in which the tube is detached from the clamping system. However, this elastic holding force is only useful in the pre-installed state, before clamping. In the clamped state, conversely, without affecting the clamping quality, it is desirable to deform the lugs to press into the band of the collar. However, if the elastic modulus of the lug is high, in some cases, especially for large diameter collars, the latter characteristic may be difficult to achieve. Furthermore, if the modulus of elasticity is too high, the engagement thrust required to grip the lugs on the gripping surfaces of the tube may be high and difficult to achieve in the event of final installation.

Therefore, although the system of EP 2 598 785 is satisfactory for a large number of applications, it is desirable to propose another solution allowing pre-installation of a clamping system at the end of the first pipe substantially free of the abovementioned disadvantages, in particular Yes for large diameter collars.

EP 1451 498 proposes a system that allows pre-installation with respect to the pipe, using pre-installation lugs also carried out by the belt through the gaskets that come with the belt. The same problem as above can also arise in pre-installation with respect to a single tube.

Other clamping systems are also known comprising a collar and a washer carried by the collar, the washer having internal lugs that can be clamped within one of the tubes for pre-installing the clamping system at the end of the tube. It may be useful to complete the system and also allow for pre-installation with respect to another tube. For this it is possible to use the long lugs proposed by EP 2 598 785, but especially for large diameter collars, another solution is needed, essentially free of the abovementioned disadvantages.

SUMMARY OF THE INVENTION

In general, there is a need for a clamping system that allows a controlled fixation in a pre-installed state relative to the clamping surface of one of the tubes intended to be clamped.

Accordingly, the present disclosure relates to a gripping system for connecting a first tube and a second tube, the opposite ends of the first and second tubes having gripping surfaces protruding from the cylindrical outer surface of the tube , the system includes a collar including a strap capable of being clamped about the gripping surface, the strap having first and second sides defining therebetween an interior capable of receiving the gripping surface The groove, the collar carries at least one securing finger, the securing finger having a free end portion projecting axially beyond the edge of the first side, the free end portion having a free end portion configured to be secured on the Ribs on the outside of the belt.

Thus, when the first tube is fitted into the clamping system, the fixing fingers are naturally in a ready state to cooperate with the elements projecting radially therefrom. Thus, once the first tube has been fitted into the clamping system, no special manipulation is required to achieve the fixation.

Optionally, the clamping system includes a centering surface located axially outside the edge of the first side surface.

Optionally, the centering surface includes at least one centering surface formed on the fixation finger.

Optionally, the collar carries at least one centering finger projecting axially beyond the edge of the first side face, and wherein the centering surface comprises at least one centering surface formed on the centering finger.

Optionally, the fixing fingers have slopes at the ends of their free end portions.

Optionally, the fixation finger has at least one reinforcing rib.

Optionally, the centering finger has a slope at the end of its free end portion.

Optionally, the centering finger has at least one reinforcing rib.

Optionally, the clamping system includes a washer supported by a collar, the washer including an annular portion placed inside the strap and carrying the securing fingers.

Optionally, the gasket also carries centering fingers.

Optionally, the ribs are formed on pins cut out in the fixing fingers and deformed radially.

The present disclosure also relates to a gripping system according to the present disclosure and a first tube having a gripping surface protruding from its cylindrical outer surface in the vicinity of its free end, the first tube further having A retaining projection on the other side relative to the clamping surface of its free end, with which the rib cooperates when the first tube is fitted into the collar.

Optionally, the fixing protrusion is formed on a transverse blade having a fastening portion and a fixing portion, which is fastened to the first tube by the fastening portion, the fixing portion being radially relative to the fastening portion Straighten.

Optionally, the blade has two securing parts and the collar carries two securing fingers, the securing fingers being configured to cooperate with the securing parts.

Optionally, the securing protrusion is configured to define an angular wedge of the clamping system relative to the first tube.

Optionally, the blade has two shoulders which form radial stops for securing the fingers.

The present disclosure will be clearly understood and its advantages will better appear on reading the following detailed description of one embodiment, presented by way of non-limiting example.

Description of drawings

1 is a perspective view of an assembly including a clamping system and two tubes according to the present disclosure.

Figure 2 shows a side view of two tubes pre-assembled due to the clamping system.

Fig. 3 is a view similar to Fig. 1, showing a variant.

Figure 4 shows a first tube suitable for this variant.

Figure 5 is a detailed view showing the pre-assembly of two tubes using the clamping system according to this variant.

Figure 6A is a schematic view of a half-section taken in a plane containing the fixation finger of Figure 5, the plane being defined by the axis A and the diameter of the band passing through the fixation finger.

FIG. 6B is a view similar to FIG. 6A for a modification.

Detailed ways

First, FIGS. 1 and 2 will be described. As can be seen from these figures, the clamping system comprises a collar 10 of the same type as described in EP 2 598 785 and a washer 28 , with which the collar cooperates to assemble the two tubes 2 , 4 .

In the following, a "radially inner" element refers to the element oriented towards the axis A of the two tubes placed end-to-end, and is the element closest to this axis A with respect to other elements called "radially outer" elements , "radially outer" elements refer to those elements oriented away from the axis A. It can also be considered that the axis A of the two tubes is also the axis of the collar, more specifically the axis of the collar strip, which wraps around itself.

Furthermore, a second element will be considered "outer" or "axially outer" of a first element if it is located beside the first element, that is, outside of the axial slice occupied by the first element ".

The collar comprises a band 12 which defines a groove 14 into which a bearing surface 18 belonging to the first tube 2 and a bearing surface 20 belonging to the second tube 4, respectively, can be inserted. This groove and these bearing surfaces have a shape such that the clamping force of the straps of the collar forces the ends of the tubes 2 and 4 towards each other. The grooves 14 are defined between the first side 13A and the second side 13B of the belt 12, which in this case define the branches of the V visible in axial section. Thus, the belt 12 has an advantageously V-shaped axial cross-section, while the bearing surfaces 18 and 20 have diameters that gradually increase towards the opposite free ends of the tube and have, for example, a frustoconical shape.

Band 12 has ends 12A and 12B, respectively, which are substantially radially straightened to form bearing lugs. The lugs are perforated to allow the rod 24A of the clamping screw 24 to pass through the lugs. The head 24B of the screw is wedged relative to one of the bearing lugs, in this case the lug 12B, while the nut 26 is fixed relative to the other bearing lug 12A. It will be appreciated that the rotation of the nut in the screw-in direction brings the bearing lugs closer to each other, thereby reducing the inner diameter of the collar, that is, allowing the strap to be clamped. Of course, other ways of clamping the straps are also conceivable, such as hooking systems, as described in particular in patent application FR3 008 160.

The clamping system includes a washer 28 which is secured to the collar. The gasket may in particular be of the type described in EP 1451 498.

The gasket 28 has a frustoconical annular portion 30 which can be inserted between the opposite ends of the two tubes 2 and 4 when the two tubes 2 and 4 are engaged in the clamping system . In fact, the washer 28 is fixed relative to the band, in this case relative to its second side 13B, by means of the fastening lugs, so that the annular space is arranged between the second side and the washer. The free end of the second tube 4 carrying its bearing surface 20 is inserted into this annular space within the groove 14, while the free end of the first tube 2 carrying its bearing surface 18 is inserted into the annular space relative to the gasket. On the opposite side, that is to say against the inner face of the frusto-conical portion 30 of the washer 28 .

In this case, the end of the tube 4 is an inner flared portion whose inner circumference of the bearing surface 20 forms the flared portion. The free end of the first tube 2, on the other hand, is the male end, which has, outside its bearing surface 18, an outer circumference 23, the diameter of which decreases gradually towards the end of the free end. Thus, the end portion 23 thus formed can be inserted into the flared portion formed at the end of the tube 4 in a substantially form-fit manner. The frustoconical annular portion 30 of the gasket 28 may have an annular deformation 32 forming a seal between the inner surface of the flared portion 19 and the outer periphery 23 .

The fastening of the gasket 28 of the collar 10 and/or the pre-assembly of the clamping system comprising the collar and the gasket on the pipe 4 can be done in the same way as in EP 1 451 498, namely by means of the fastening lugs provided by the gasket Lugs and/or pre-installed lugs 34 for hooking the gasket on the second side 13B of the strap, while arranging the aforementioned annular space, as described in EP 1 451 498.

Other modes of tightening the washer to the collar can be used. For example, the washer may have a retaining ring in which the shank of the screw 24 may engage, or one or several retaining lugs that are secured to the strap, for example by hooking or pinching on the edge. Likewise, other modes of pre-installing the clamping system with respect to the tube 4 can also be used, eg by equipping the gasket with internal lugs or studs that engage in the tube 4 to snugly against the inner surface of the tube 4 .

The collar carries fixing fingers 40 having free end portions projecting axially beyond the edge of the first side face 13A. For each securing finger, the free end portion has a rib 42 that is configured to be secured to the outside of the strap by means of radially projecting elements. This radially protruding element is in particular a fixing projection fixed to the first tube 2, as shown below. The inner surface 43 of the common part of the fixing fingers forms a centering surface which extends axially beyond the edge of the first side face 13A while being radially included in the diameter dimension of this edge. Taken together, the different centering surfaces define a diameter dimension comparable to that defined by the top of the clamping surface 18 of the first tube 2 in order to center the first tube when it is inserted into the clamping system. It can be seen that the collar also carries centering fingers 50 which are similar to the fixing fingers except that they do not have ribs. However, for fixed fingers, their inner surfaces 53 form the centering surfaces. It can be seen that the fixation and centering fingers have ribs 48 which are axially oriented and reinforce the fingers. Thus, the fixing and centering fingers are radially responsive, that is, they are relatively inflexible and can be radially elastically deformed at small radial displacements by having a strong tendency to elastically recover. The fixing and centering fingers also have flared ramps 49 at the ends of their free ends. These flared ramps facilitate insertion of the first tube into the clamping system.

In this case, the fixing fingers 40 and centering fingers 50 are carried by the washer 28, which is itself supported by the collar 10, as shown. More specifically, the fixing and centering fingers are carried by the annular portion 30 of the gasket, in this case a frustoconical annular portion, which is placed within the band 12 of the collar. A securing finger and a centering finger extend forwardly from the leading edge of the annular portion. Within the meaning of the present disclosure, the forward direction is the direction from the second side 13B towards the first side 13A. Thus, the securing and centering fingers extend forward beyond the leading edge of the side face 13A. The forward direction is indicated by arrow F in FIG. 1 . In the unclamped state of the collar, the retaining and centering fingers may extend substantially axially forward from the leading edge of the annular portion 30 of the washer 28 . In particular, they may extend parallel to the axis A, at least in the common part between their ends. However, in the portion where they are attached to the gasket 28 , they may be slightly corrugated radially outward to be closer to the bottom of the groove 14 of the band 12 . Furthermore, the stiffening rib can only start at a short distance from the connection between the fixing and centering fingers and the washer, in order to allow some flexibility in this connection between the lug and the washer, while ensuring that the front Referring to the responsiveness, it should be noted that the radially outer surfaces of the fingers may cooperate with the edges of the first side to facilitate elastic recovery of these fingers radially inwards. It will be appreciated that when clamping the collar, two tubes are connected at the same time, and these parts for connecting the fingers to the gasket are deformed by being pressed against the bottom of the groove by the clamping surface 18 .

As can be seen in FIGS. 1 and 2 , the first tube has fixing projections 62 which protrude radially on its outer surface and are located on the clamping surface 18 with respect to the free end 2 ′ of this first tube 2 on the other side. More specifically, a fixing protrusion 62 is formed on the transverse blade 60 having a fastening portion 60A and a fixing portion which is fastened to the first tube by the fastening portion, the fixing portion forming the fixing protrusion 62 , and straightened radially relative to the fastening portion 60A. In fact, the fastening part is connected to the fixing part by the step 60B. In this case, the transverse vanes 60 have the shape of flat vanes, the thickness of which is measured radially and the width of which is measured parallel to the axis A of the collar. More specifically, in the example shown, the transverse blade has two similar fixing portions 62, which in this case are placed at the two ends between which the fastening portion 60A extends.

As can be seen in FIG. 2 , each of the two fixing fingers 40 cooperates with one of these fixing portions 62 by means of its fixing pin 42 . In FIG. 2 , the two tubes are pre-assembled and the clamping system is pre-installed at the end of the second tube 4 and at the end of the first tube 2 . In this case, clamping the collar is sufficient to complete the assembly of the two tubes. In this way, as described above, the fixing lugs and the centering lugs are deformed under the clamping action without hindering the latter.

Referring to Figures 3 to 5, the variant will now be described. Compared to the clamping system of Figures 1 to 2, the clamping system itself is unchanged. A variation of this variant is that the system is combined with the first tube, allowing wedging of the clamping system relative to the angle of the first tube. In fact, the transverse vanes 70 carried by the first tube 2 and on which the fixing portions 72 forming the fixing protrusions are formed are slightly different from the vanes 60 previously described, except that these fixing portions 72 are connected thereto by means of steps 70B. On the fastening portion 70A, the step 70B extends radially outwardly through radially projecting ears 70C. These ears are simply made by folding transverse leaves. As can be seen in FIG. 5 , the angular spacing of the ears 70C is adjusted so that in the pre-assembled state the ears extend between the two fixing fingers 40 and are fixed by their pins 42 on the leading edge of the fixing portion 72 . This allows to ensure the wedging of the second tube relative to the angle of the clamping system.

The shaping of the transverse vanes 60 or 70 allows a particularly efficient pre-assembly. In fact, as shown, the thickness of the vane is oriented radially, while its width is oriented axially. The fixing fingers are fixed on the leading edge of the fixed part of the blade, that is to say the edge furthest from the free end of the first tube. Any force separating the first tube from the locking system operates parallel to the width of the transverse vanes. Therefore, it is the direction in which the blade is less likely to deform. Therefore, pre-assembly is particularly effective. The ears 70C of the blades 70 form shoulders in the form of radial stops for securing the fingers 40 .

For the installation of the assembly comprising the two tubes and the clamping system, the free end of the tube 4 is first engaged in the annular space arranged between the gasket 28 and the second side 13B of the strap in order to pre-install the clamp around this free end The clamping system is then engaged with the free end of the tube 2 in the clamping system until the position shown in FIGS. 3 and 5 is reached.

During assembly of the first tube into the clamping system, the centering surface allows cooperating with the top of the clamping surface of the first tube to center it relative to the clamping system. This facilitates the correct pre-installation of the clamping system on the first tube and thus centers the two tubes relative to each other. The centering surface may be formed on the stationary finger, possibly by one or several centering surfaces formed on the centering finger (if provided). The rib that secures the finger can be made in a very simple manner by means of a simple partial cut in the finger to release the folded back lugs to form the radially inwardly folded pins 42 . The pin is very simple to manufacture, without the need for additional material, while forming an effective claw, allowing the fixing fingers to grip on radially projecting elements on the outer circumference of the first tube.

FIG. 6A schematically shows the first tube 2 , the second tube 4 , the collar 12 , the gasket 28 and the transverse vanes 40 . The frustoconical portion 30 of the gasket 28 is located between the inner surface of the bearing surface 20 of the second tube 4 and the outer surface of the frustoconical end 23 of the first tube 2 . On the one hand, the clamping system is pre-installed on the second tube 4 , the pre-installation lugs 34 of the gasket on the one hand hook the gasket on the band 12 of the collar, and on the other hand bear on the outer surface of the clamping surface 20 . On the other hand, the clamping system is also pre-installed on the first tube, the fixing fingers 40 are fixed on the fixing part 72 of the blade 70, the pin 42 is fixed against the leading edge of the fixing part. In this example, as shown in the previous figures, the fingers pass radially over the securing portion 72 until hooked on its leading edge.

FIG. 6B shows a variant which differs from FIG. 6A in that the fixing fingers 40 ′ pass radially under the fixing part, which in this case is similar to the fixing part 62 . In effect, the fixing fingers 40' extend axially forward from the frusto-conical portion 30 of the gasket, while maintaining a diametrical dimension that allows radial passage through the fixing portion during insertion of the end of the tube 2 into the clamping system 62 below. Thus, the radially outwardly directed securing pins 42 ′ of the fingers 42 can hook on the leading edge of the securing portion 62 . The ramps 49' formed at the free ends of the fingers 40' point inwards. The fixation fingers 40' may also be similar to the fixation fingers 40 in the previous figures, and in particular have centering surfaces and reinforcing ribs.

As shown, the securing protrusions may be formed on transverse vanes fastened to the first tube. The blade is a very simple and therefore easy-to-manufacture geometric element. However, since there may be contact surfaces between the first tube and the vane, its fastening may be very limited. The transverse orientation of this vane promotes an efficient fixation, since possible separating forces operate axially, thus perpendicular to the main direction of the vane, in which the vane is less prone to deformation.

The clamping band and washers as well as the fingers are preferably made of metal. Washers, in particular, can be made of austenitic stainless steel strips, the thickness of which is comprised in particular between 0.1 mm and 0.5 mm, even between 0.2 and 0.4 mm.

Claims (16)

1. Clamping system for connecting a first and a second pipe (2, 4), the opposite ends of the first and second pipe having clamping surfaces (18, 20) protruding from the cylindrical outer surface of the pipes, the system comprising a collar (10) comprising a band (12) capable of being clamped around the clamping surface, the band (12) having first and second side faces (13A, 13B), defining an internal groove (14) therebetween capable of receiving the clamping surfaces (18, 20), the clamping system being characterized in that the collar carries at least one fixing finger (40, 40'), the fixed fingers have free end portions projecting axially beyond the edge of the first side face, the free end portions having ribs (42, 42') configured to be fixed on the outside of the belt by means of radially projecting elements.

2. Clamping system according to claim 1, comprising a centering surface (43) axially outside the edge of the first side face.

3. The clamping system of claim 2, wherein the centering surface comprises at least one centering surface (43) formed on the fixed finger.

4. Clamping system according to claim 2, wherein the collar carries at least one centering finger (50) axially protruding beyond the edge of the first side face, and wherein the centering surface (53) comprises at least one centering surface formed on the centering finger.

5. Clamping system according to claim 1, wherein the fixing finger (40, 40') has a ramp (49, 49') at the end of its free end portion.

6. Clamping system according to claim 1, wherein the fixing finger (40, 40') has at least one reinforcing rib (48).

7. Clamping system according to claim 4, wherein the centering finger (50) has a ramp (49) at the end of its free end portion.

8. Clamping system according to claim 4, wherein the centering finger has at least one reinforcing rib (48).

9. Clamping system according to claim 1, comprising a washer (28) supported by said collar (10), said washer comprising an annular portion (30) placed inside said band (12) and carrying said fixing fingers (40, 40').

10. Clamping system according to claim 4, comprising a washer (28) supported by the collar (10), the washer comprising an annular portion (30) placed inside the band (12) and carrying the fixing fingers (40, 40') and at least one centering finger (50) axially projecting beyond the edge of the first side face, the centering finger (53) comprising at least one centering surface formed on the centering finger.

11. Clamping system according to claim 1, wherein the rib (42, 42') is formed on a pin cut in the fixed finger (40, 40') and is radially deformed.

12. An assembly comprising a clamping system according to claim 1 and a first tube (2) having, in the vicinity of its free end, a clamping surface (18) projecting from its cylindrical outer surface, the first tube further having, on the other side of its clamping surface (18) with respect to its free end (2'), a fixing projection (62, 72) with which the rib cooperates when the first tube is fitted into the collar.

13. The assembly according to claim 12, wherein the fixing projections are formed on a transverse blade (60, 70) having a fastening portion (60A, 70A) by which it is fastened to the first pipe and a fixing portion (62, 72) which is radially straightened with respect to the fastening portion.

14. The assembly of claim 13, wherein the blade has two fixed portions (62, 72) and the collar carries two fixed fingers (40, 40') configured to mate with the fixed portions.

15. The assembly according to claim 12, wherein the fixing projection (62, 72) is configured to define an angular wedging of the clamping system with respect to the first pipe (2).

16. The assembly of claim 15, wherein the vane (70) has two shoulders (70C) forming radial stops for fixing fingers (40, 40') carried by the collar and configured to cooperate with the fixing portion.

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